Harpswell remains chem-free, for now, against invasive plants

HARPSWELL — There are two upcoming opportunities for volunteers to help remove invasive species at Mitchell Field.

Jane Covey, chairwoman of the Mitchell Field Committee and a member of the Harpswell Invasive Plant Partnership, also announced at the Aug. 4 Board of Selectmen meeting that HIPP will not use herbicides to treat specific species until it conducts further research into the potential costs.

As part of effort to combat the town’s growing invasive species problem, volunteers on Sept. 10 can help remove bittersweet from trees on the Mitchell Field perimeter.

The other date is yet to be scheduled, but will take place this month and be dedicated to removing knapweed from the area. Residents can visit HIPP’s Facebook page to find out how to get involved.

The Maine Natural Areas program defines an invasive species as “a plant that is not native to a particular ecosystem, whose introduction does or is likely to cause economic or environmental harm or harm to human health.”

The problems impact many communities – the Natural Areas Program reports approximately 2,100 invasive species have been identified in Maine alone – but the issue is especially dangerous for Harpswell, where the environment and the economy are tightly intertwined.

In response, HIPP was formed in early 2015. The partnership is a collaboration between the Harpswell Heritage Land Trust, the Town Lands Committee, the Conservation Committee, the Mitchell Field Committee, the Recreation Committee, the Harpswell Garden Club, and local volunteers.

Last year the partnership surveyed three land trust preserves, three town lands, and 28 miles of highway roadside. As a result, HIPP decided to focus on 16 invasive plants, and has since begun hosting workshops and posting information about how to properly identify and remove them. For more information on how to identify invasive species, visit HIPP’s page on the Harpswell Heritage Land Trust website.

When invasive species take over a landscape, “everything just goes downhill,” Jeff Stann, a member of HIPP and an invasive plant expert, said in a phone interview.

Stann said farms are an obvious example. “If you’re a farmer,” he said “and an invasive plant takes over your field, it can get in the way of whatever you’re growing.”

Invasives are insidious in their spread, and what can begin as a weed along a road can later escalate to an infestation that throws off the entire balance of an ecosystem.

“Non-native plants don’t support bird, insect, and microbial life” local to the area, which ultimately causes a cascading effect that diminishes the number of pollinators and animal species that call Harpswell home, Stann said.

The upcoming Mitchell Field volunteer opportunities are temporary solutions to stop the immediate spread of invasives like knotweed and bittersweet, while the Mitchell Field Committee continues its “due diligence” in researching a formal management plan for the field and other major town properties, he said.

The caution is predicated on the delicacy of the natural ecosystems already under threat. In other words, the committee is wary of implementing a management plan that can cause damage as well.

Looking into the future, “we have to think of the total ecology of the place,” Covey said. “(What if) there are invasive plants that are helping to stabilize the bluff line?”

In that case, she said, the committee would have to consider the possibility of compensating for their removal by replacing them with appropriate native plants that will prevent erosion on the bluff.

But that’s just an example. The committee is still in the early stages of formulating a formal comprehensive plan, which will likely involve consulting outside experts, as well as a difficult cost/benefit analyses, such as whether to employ the use of herbicides to combat the issue.

“The committee’s approach would be to use non-chemical means where possible and effective,” said Covey. At the Aug. 4 selectmen’s meeting that, she stated that for the time being, the committee will only use mechanical means to remove plants.

But she acknowledged that the town will have to weigh the cost of chemicals against the potentially larger threat of the overall invasive problem, and those kinds of decisions take time.

The Mitchell Field Committee hopes to have an attack plan in place by early next year, she said.